[msan] Mprotect all inaccessible memory regions.

Fix 2 bugs in memory mapping setup:
- the invalid region at offset 0 was not protected because mmap at
  address 0 fails with EPERM on most Linux systems. We did not
  notice this because the check condition was flipped: the code was
  checking that mprotect has failed. And the test that was supposed
  to catch this was weakened by the mitigations in the mmap
  interceptor.
- when running without origins, the origin shadow range was left
  unprotected.

The new test ensures that mmap w/o MAP_FIXED always returns valid
application addresses.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@238109 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/msan/msan.cc b/lib/msan/msan.cc
index 8f741de11..dd72c9da6 100644
--- a/lib/msan/msan.cc
+++ b/lib/msan/msan.cc
@@ -390,7 +390,7 @@ void __msan_init() {
   __msan_clear_on_return();
   if (__msan_get_track_origins())
     VPrintf(1, "msan_track_origins\n");
-  if (!InitShadow(/* map_shadow */ true, __msan_get_track_origins())) {
+  if (!InitShadow(__msan_get_track_origins())) {
     Printf("FATAL: MemorySanitizer can not mmap the shadow memory.\n");
     Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
     Printf("FATAL: Disabling ASLR is known to cause this error.\n");